Radio power-supply unit



Au 14; 1928. 158E370 P. E. EDELMAN RADIO POWER UPPLY UNIT Filed March 25, 1925 IN V EN TOR.

- transformer as primary source not comprise a put when a rectifier of small mllliamperage 7 Further,

Patented Aug, 14, 1928-.

.UNITEDp STA rmmrn EDELMAN, or CHICAGO, rumors.

RADIO POWER-SUPPLY UNIT.

, Application filerlliarch 23, 1925. Serial No.17,489.

This invention comprises certain new and useful arrangement of coacting electrical elements whose generic object isto provide a small compact electrical convertor unit having a plurality of output circuits suited for furnishing power supply to the cathode heating and the anode to cathode circuits of radio vacuum tubes, provided withmeans for eliminating objectionable-hum iii-said output circuits, provided further with a grounded enclosure for said electrical'elements whereby induction therefrom with respect to the ground is prevented from reachingv radio apparatus to which said unit is to be connected. More specific objects of this invention provide a common for all 0utput circuits whereby the variations in current draw. from each of said circuits tend to cooperate in the regulation of the com bined output of said transformer... Also choke coils "are distributed on both sides of the output pilot conductors ing fluctuations of current in the output due to capacity leakage with respect to the ground potential are eliminated. Further the output potential intended. for plate supply to vacuum'tubes of a r'adio set is adjustable via series resistances whlch do shunt load limiting the outoutput-is used in the power unit, and not cause the loss and voltage drop that a shunt potentiometer type of load regulator would. A further specific improvement comprised in this invention isthat the now be made much smaller in size than formerly required due to. the operatlon of .the filter system's starting at source en with much higher potential than at output end, each successive lower potential than the, precedingstage, and in the case of the filament supply output circuit, the first storage cellsg-having a higher output terminal voltage than the .next cells of the series, thereby overcoming the. resistance effect of smaller size of chokev coils employed,:-- so that a compactumt of small dimensions is obtained. The grounded enclosure for the elements also assists in dissipation of heat arising during operation. to avoid radio frequency-currents travelling back thrujthe pilot conductors of output. circuits is a detail of one sources of direct current main power supply,

whereby remainformer 3 has a .storage elements and the choke coils can P windings d to the winding ,5,

sta e 0 eratin at a g p g core choke coils 14, 15,

. to cause undesired regener-' gtive feedbac efi ts e'req gsa tc wnwu this unit suppliespower,.the end terminals .ofsaid power unit-are shunted with by-pass condensers, and the terminals are provided for universal use whether the connected .ra- ;dio set requires B minus. to A minus, binding post connection. Reference is made to the accompanying drawing of which Figure 1 is a diagram of the radio'power su ply unit, and Figure-2 o? thecell elements 40 of Fi ure 1, shown in frontelevation.

Bresent invention has for its object to provide a unit attachable to an alternating current lighting socket, to provide plural for use in operating one to eight, or more, current supply for both the. filaments and the plates thereof. A further object is to accomplish the said result with an; inexpensive compact unit insulated from the provided with means. therein, and adapted to care for heat arising minus to A plus or B vacuum tubes, as a to furnish constant sources of direct current free .from objectionable alternating ourl rent hum. The nvent on comprises certain. .new com'blnatlons whereby said result is attained and various changes may be made,

without departingfrom the general means set forth, Within the scope of the appended claims] a Referring now, ure 1-an ordinary attachment plug 1, con-- nects by a flexible, cord. conductor 60, via a fuse 2, to the primary winding 4:, of-an alternating current transformer 3. 'This transplurality of secondary out- 6, 7 and 8, and is constructed in usual closed core manner well known in the art; An impedance coil 10, is connected andhas a divided winding I 11, 12 with a middle connection 13. -The more particularly, to Figi i terminal 13, connects with a series of closed 16, 17., wire 61, and NJIost 32' This terminal 32, may

inns B, indicating that this the terminal be labeled .is the correct connection for the minus B binding post or terminal of a standard radio "One terminal 62, .of'transformer coil 5, is also connected to an anode 51, of rectifier 45. The. cathode 48, of rectifier 45,

connected to transformer winding 7, v1a

rheostat' 43. @The cathode 48, is connected to choke coil- 94; thenceto choke. 0011 27 into rheostatsfifi, 26,:then to wires 63,. 64 and te minal post .31; 3 Te mm l pest amount of current which resistances 25 or 26 can pass takes an appreciable time to flow from condenser 23 through the high resist-' ance thereof and in the meantime this condenser 23 receives a fresh charge. This effect is similar to a fly wheel on an engine provided with governor and smoothes out the current to prevent sudden fluctuations as "the load varies or the input voltage to plug 1 changes. Also these resistances 25 or 26 being in series connection do not act as a power controlling load on the circuit except when current is passing through said resistances for useful purpose in actuating the connected radio set.

A plurality of by-pa'ss condensers 19, 20,

21, 22, 23, are respectively connected be-- tween the choke coils 14 and 24, 15 and 24, 16 and 24, 17 and 24,18 and 24, to serve as a storage and filter system; These condense ers maybe of the well known paper or mica type. The 'sizes of the said choke coils and the said condensers are. proportioned asis well known in the art, in accordance with the alternating current frequency of the source used to supply the transformer 3, and to take care of harmonics thereof. The combined inductance. of the choke coils above enumerated may, for example, be fifty henries, while the combined capacity of the condensers enumerated above, may,

.. for example, be 'six micro-farads.

tially 45,-even when the'cathodes 47, 48, are dis-v in the rectifier tubes Two terminal condensers, 28, 29, are connected between the posts 30, 31, and 32, as shown and'are preferably placed at the ends of wires 64, 63 and 61, which are intended to reach near to the connected radio set (not shown) in order that any radio frequency currents may not need .to flow thru-wires 64, 63 and 61.

A second rectifier 44, is similarly connected with its anode 52, supplied by transformer winding 5, and with its cathode'47,

supplied. by transformer winding. 7, via rheostat 43'. The function. of the impedance coil 10, is to balance the currents fed to the two anodes 52,- 51, whereby both half cycles of the alternatlng current will be substanequally rectified by he rectifiers 44,

similar in dimensions, or when the vacuum 44, 45, vary from each other. r

The-above'description covers a full wave rectifier supplying a'special series filter with an adjustable potential output, having terminals .provided with 'by-pass condensers 28, 29, and would still be operative if either the rectifier 44, or 45 were omitted, in such case usingonly one rectlfier for half wave rectification. Instead of vacuum tube type of rectifiers,.electrolytic or mechanical types cathode 49, is heated by transformer winding 8. One terminal 65,- of transformer winding 6, is connected to a choke coi139. One terminal 66,- of transformer winding 8, is connected to a choke coil 38. A current storage unit 40, is connected to choke coils 38 and'39. This unit may comprise a small sized storage battery or may comprise one or more electrolytic condensers, or, electrolytic rectifiers such as the aluminum-lead or tantalum-lead types, well known in "the art. The storage unit 40, may be of the leadacid-lead type or of the nickel-alkaline-iron type in case it is comprised as a floating battery instead of an electrolytic condenser.

A second current storage unit 41, is connected; to the unit 40, via a choke coil 37. If desired, and as shown, a third current storage unit 42, may be connected to the first and second above named storage units -.via a choke coil 35; this'may be continued in similar cascaded connections as far'as. vmay be necessary. to remove notlceable alternating current fluctuations. .Usually it suffices to have two orat most three of such.

cascaded current storage units to obtain'a terminal direct current source which is practically free from alternating current ripples. If desired, a rheostat 59, may be included tovary a current obtainable at the terminals '33, and 34. Terminal 33, may be.

labeled Plus A while terminal 34, may be labeled Minus A.

metal container 53, having vent holes 67, is provided to house the above named elements and is electrically connected by wire 68 to wire 69, and grounded. A unit' of thls description which I have constructed and used has a box 53, of size. 8x10x10.

- The above continued description has covered the part of the unit comprising means for supplying filament current to vacuum tubes. Owing to the current storage units described, the filaments of one to eight ormore standard .vacuum tubes, (not shown) can be heated'in usual parallel connection.

The several choke coils above described are preferably constructed with laminated iron- In the case of the choke coils closed cores. 37, and 35, it is desirable to have relatively large sized wire for the coils thereof and to proportion the resistance. of eachfwinding so thatv the direct current resistance thereof I will-be approximately in proportion to the dlfierenc'e in potential between the current storage unit 142, and 41, or the 41, and

-current storage unit ticed that this arrangement 0 40 in Figure have four such cells while t three cells and the unit 42, has three such ,two cells of the well known a the terminal potential of the unit 41, may

be 6.6 volts, and the terminal potential of the 42, may. be only 6.1 volts. Similarly in the case of the plate filter rectifier the transformer winding 5, will have a higher otential than the out- 'ut potential of said filter. It will be nois suitable for connection to any standard known type of radio set using one to eight-or more vacuum.

tubes without requiring any changes '11! the usual operation, construction or arrange- 1 .ment of said radio set.

- VVhilethe current storage units may be constructed in manner well known in the art, a preferred arrangement is indicated in Figure2. .Aglass or rubber'container 54,

2 is provided with a cover 70, which holds electrodes 56, 55, so that they are'partly covered by the. electrolyte or jellied-electrolyte 57, contained in the container 54.- The materials of 56, 55 and of 57, may be selected as 25 hereinbefore. set forth to comprise either an electrolytic condenser or a secondary battery and one or more cells of the kind indicated by Figure 2, may comprise a current storage unit such as indicated by the numeral 1. For example, if lead-acidleadcells are used the 'storagp unit40, may e unit 41, has

rise'one or uminum-alkaline-lead or tantalumacid-lead type, while the unit 41, and the unit 42, comprise'stor- .age oellsof the battery type,.as set forth. In any case the unit 40, will be at a higher potential than the unit 41, and the unit 41, will be at a higher otential than the unit 42. In this manner t e units 41, and 42, are

, floated on the. rectifier output but the choke coils arranged as set forth elminate alternatcells; Or the unit 40 may com ing current ripples, which would otherwise be objectionable in the radio set w which the radio power unit is to be connected; Even slight alternating currentripples are objectionable'because they reach the sensitive grid of a vacuum tube in a set power unit is connected, and that is why at at least two, and preferably three cascaded- 42, are used.

units, such as 40, 41, and

2, the cell top 70,

As indicated by Flgure which occur the combination being grounded, ply being isolated to which the radio u ly .is, provided with a'gas vent tube 58, and'the sorbing or converting small amounts of gas during operation. I claim 1. A radio power supply unit comprising a transformer, means to connectsaid transformer to a source of alternating current, a plate current supply fed by said transformer, aseries cascaded filter connected to said plate current supply and including adjustable series resistances to adjust the "output potential thereof and to prevent the-sudden discharge of current therefrom, a filament current supply fed by saidsource of alternating current, and a metallic container for enclosing said plate and filament current suplies and grounded to one of said supplies.

2. In a radio power supply unit, the combination of a transformer, plate current supplies energized from said transformer, and means for suppressing magnetic lines of force extending from said transformer and. associated apparatus, comprising a metallic container for enclosing said transformer and associated apparatus, said container being connected to one of the terminals of the filament current supply.-

3. In a radio power supply .unit, the combination of a transformer, a re'ctifier connected thereto, a filter circuit operatively connected to said rectifier, saidfilter circuit having a plurality of output terminals, an

means for reducing the potential at the terminals of said filter circuit and limiting the rate of discharge of current therefrom, com-. prising resistances connected between the filter circuit and one or more of the output terminals.

*4. In 'a.v radio power of a transformer, fed thereby, a

supply unit,

current supply filament current supply, each of said supplies, minals of the one of the terfrom said filament current except when the power supply unit is con -ted toI a load.

In witness whereof, I have hereunto set jmysignature this 19th day of March, 1925.

PHIL IP E. EDELMAN.

a plate I and output terminals for filament current supplysaid plate current sup-- filament and i 

